Process for the manufacture of 4-aminobenzene-nu1-(3&#39;:4&#39;-dimethylbenzoyl)-sulfonamide



Patented Mar. 4, 1947 PROCESS FOR THE MANUFACTURE OF 4- AlVIINOBENZENE-N(3:4'-DIMETHYLBEN- ZOYL) SULFONAMIDE Henry Martin and Otto Neracher,Basel, Switzerland, assignors to the firm of J. R. Geigy A. G.,

Basel, Switzerland No Drawing. Application March 27, 1944, Serial No.528,340. In Switzerland April 9, 1943 4 Claims.

The condensation of p-nitrobenzene sulfene chloride with acetamide andsubsequent oxidation of the acetylated p-nitrobenzene sulfenamide top-nitrobenzene sulfone acetamide is known.

However, the same interaction cannot be carried out with tetramethylbenzamide, the arcmatic acids, which are rich in alkyl groups, beinglargely decomposed and destroyed on oxidation.

Surprisingly we have now found that the oxidation of p-nitrobenzene-Ni-(3' :4-dimethy1benzoyl) -su1fenamide can nevertheless be carried out. Ofcourse this fact could not be presumed.

The invention i illustrated, but not limited by the following example,wherein the parts are by weight.

Example 1 part of 3:4-dimethyl benzamide is dissolved at 30-40 C. inparts of absolute pyridine and slowly heated with .1 part of4-nitrobenzene-sulfene chloride. After a short heating on .thewater-bath the mixture is poured into ice-cold diluted hydrochloricacid. The precipitation thus separated is filtered, dried andrecrystallised from absolute benzene. Thus colorless prisms areobtained, the same havingthe melting point of 158 C.

1 part of 4-nitrobenzene-N1-(3z4' dimethylbenzoyD-sulfenamide isdissolved in 50 parts of acetone and, while stirring, dropwise treatedat room temperature with a 3% potassium per manganate solution inacetone, until the red coloration remains unchanged. Then there israpidly sucked oil and the 4-nitrobenzene-N1-(3' :4-dimethylbenzoyll-sulfamide melting at 192 C. is recovered byconcentration of the acetone solution. By reduction it can be convertedinto paminobenzene-sulfone-3 4-dimethy1 benzamide.

The oxidation can also be performed with hydrogen peroxide instead ofpotassium permanganate.

- Number What we claim is:

1. In a process for the manufacture of 4-aminobenZene-N1-(3':4-dimethylbenzoyl) sulfonamide, the step which consists in subjecting4- nitrobenzene-N1-(3 :4-dimethy1benzoyl) -sulfenamide to the action ofan oxidizing agent whereby the corresponding sulfonamide is obtained.

2. In a process for the manufacture of 4-aminobenzene-N1-(3' :4-dimethy1benzoyl) sulfonamide, the step which consists in subjecting4-nitrobenzene N1 (3' :4-dimethylbenzoyl) -sulfenamide to the action ofpotassium permanganate whereby the corresponding sulfonamide isobtained.

3. In a process for the manufacture of 4-aminobenzene-N1-(3:4-dimethylbenzoyl) sulfonamide, the step which consists in subjecting4-nitrobenzene-N1-(3' :4-dimethylbenzoyl) sulfenamide to the action ofhydrogen peroxide whereby the corresponding sulfonamide is obtained.

4. A process for the manufacture of 4-nitrobenzene N1 (3' :4dimethylbenzoyl)-su1fonamide, which comprises subjecting 4-nitrobenzene-N1-(3 :4-dimethylbenzoyl) -sulfenamide to the action of an oxidizingagent whereby the corresponding sulfonamide is obtained, and thensubjecting the resultant 4-nitrobenzene-N1-(3:4- dimethylbenzoyl)-sulfonamide to the action of a reducing agent whereby the nitro groupis reduced to amino.

HENRY MARTIN. OTTO NERACHER.

REFERENCES CITED The following references are of record in the file ofthis patent:

FOREIGN PATENTS Country Date 551,207 British 1942

